Handle some special cases of unary 2's complement,
and improve netlist expression width handling.
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steve
parent
ab11943496
commit
41242735ed
125
elab_net.cc
125
elab_net.cc
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@ -17,7 +17,7 @@
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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#if !defined(WINNT) && !defined(macintosh)
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#ident "$Id: elab_net.cc,v 1.59 2001/01/18 03:16:35 steve Exp $"
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#ident "$Id: elab_net.cc,v 1.60 2001/01/24 02:52:30 steve Exp $"
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#endif
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# include "PExpr.h"
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@ -169,9 +169,34 @@ NetNet* PEBinary::elaborate_net_add_(Design*des, const string&path,
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// If the desired output size if creater then the largest
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// operand, then include the carry of the adder as an output.
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#if 0
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unsigned owidth = width;
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if (lwidth > owidth)
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owidth = width + 1;
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#else
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/* The owidth is the output width of the lpm_add_sub
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device. If the desired with is greater then the width of
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the operands, then widen the adder and let code below pad
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the operands. If this is an adder, we can take advantage of
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the carry bit. */
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unsigned owidth = width;
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switch (op_) {
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case '+':
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if (lwidth > owidth) {
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owidth = lwidth;
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width = lwidth-1;
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}
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break;
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case '-':
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if (lwidth > owidth) {
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owidth = lwidth;
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width = lwidth;
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}
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break;
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default:
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assert(0);
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}
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#endif
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// Pad out the operands, if necessary, the match the width of
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// the adder device.
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@ -182,7 +207,9 @@ NetNet* PEBinary::elaborate_net_add_(Design*des, const string&path,
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rsig = pad_to_width(des, path, rsig, width);
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// Make the adder as wide as the widest operand
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osig = new NetTmp(scope, des->local_symbol(path), owidth);
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osig = new NetNet(scope, des->local_symbol(path),
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NetNet::WIRE, owidth);
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osig->local_flag(true);
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NetAddSub*adder = new NetAddSub(name, width);
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// Connect the adder to the various parts.
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@ -322,10 +349,6 @@ NetNet* PEBinary::elaborate_net_bit_(Design*des, const string&path,
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assert(0);
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}
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if (NetTmp*tmp = dynamic_cast<NetTmp*>(lsig))
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delete tmp;
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if (NetTmp*tmp = dynamic_cast<NetTmp*>(rsig))
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delete tmp;
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return osig;
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}
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@ -768,12 +791,12 @@ NetNet* PEBinary::elaborate_net_mul_(Design*des, const string&path,
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NetScope*scope = des->find_scope(path);
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assert(scope);
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NetNet*lsig = left_->elaborate_net(des, path, 0, 0, 0, 0);
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NetNet*lsig = left_->elaborate_net(des, path, lwidth, 0, 0, 0);
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if (lsig == 0) return 0;
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NetNet*rsig = right_->elaborate_net(des, path, 0, 0, 0, 0);
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NetNet*rsig = right_->elaborate_net(des, path, lwidth, 0, 0, 0);
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if (rsig == 0) return 0;
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unsigned rwidth = lsig->pin_count() + rsig->pin_count();
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unsigned rwidth = lwidth;
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NetMult*mult = new NetMult(des->local_symbol(path), rwidth,
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lsig->pin_count(),
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rsig->pin_count());
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@ -829,14 +852,14 @@ NetNet* PEBinary::elaborate_net_shift_(Design*des, const string&path,
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if (verinum*rval = right_->eval_const(des, path)) {
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assert(rval->is_defined());
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unsigned dist = rval->as_ulong();
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if (dist > lsig->pin_count())
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dist = lsig->pin_count();
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if (dist > lwidth)
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dist = lwidth;
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/* Very special case, constant 0 shift. */
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if (dist == 0) return lsig;
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NetNet*osig = new NetNet(scope, des->local_symbol(path),
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NetNet::WIRE, lsig->pin_count());
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NetNet::WIRE, lwidth);
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osig->local_flag(true);
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NetConst*zero = new NetConst(des->local_symbol(path), verinum::V0);
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@ -846,8 +869,11 @@ NetNet* PEBinary::elaborate_net_shift_(Design*des, const string&path,
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unsigned idx;
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for (idx = 0 ; idx < dist ; idx += 1)
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connect(osig->pin(idx), zero->pin(0));
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for (idx = dist ; idx < lsig->pin_count() ; idx += 1)
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for ( ; (idx<lwidth) && ((idx-dist) < lsig->pin_count())
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; idx += 1)
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connect(osig->pin(idx), lsig->pin(idx-dist));
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for ( ; idx < lwidth ; idx += 1)
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connect(osig->pin(idx), zero->pin(0));
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} else {
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assert(op_ == 'r');
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@ -855,7 +881,7 @@ NetNet* PEBinary::elaborate_net_shift_(Design*des, const string&path,
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unsigned keep = lsig->pin_count()-dist;
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for (idx = 0 ; idx < keep ; idx += 1)
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connect(osig->pin(idx), lsig->pin(idx+dist));
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for (idx = keep ; idx < lsig->pin_count() ; idx += 1)
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for (idx = keep ; idx < lwidth ; idx += 1)
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connect(osig->pin(idx), zero->pin(0));
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}
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@ -1664,9 +1690,17 @@ NetNet* PEUnary::elaborate_net(Design*des, const string&path,
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NetScope*scope = des->find_scope(path);
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assert(scope);
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NetNet* sub_sig = expr_->elaborate_net(des, path,
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op_=='~'?width:0,
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0, 0, 0);
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// Some unary operands allow the operand to be
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// self-determined, and some do not.
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unsigned owidth = 0;
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switch (op_) {
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case '~':
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case '-':
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owidth = width;
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break;
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}
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NetNet* sub_sig = expr_->elaborate_net(des, path, owidth, 0, 0, 0);
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if (sub_sig == 0) {
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des->errors += 1;
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return 0;
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@ -1784,19 +1818,72 @@ NetNet* PEUnary::elaborate_net(Design*des, const string&path,
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gate->decay_time(decay);
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break;
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case '-': // Unary 2's complement.
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sig = new NetNet(scope, des->local_symbol(path),
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NetNet::WIRE, sub_sig->pin_count());
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sig->local_flag(true);
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switch (sub_sig->pin_count()) {
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case 0:
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assert(0);
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break;
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case 1:
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gate = new NetLogic(scope, des->local_symbol(path),
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2, NetLogic::BUF);
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connect(gate->pin(0), sig->pin(0));
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connect(gate->pin(1), sub_sig->pin(0));
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des->add_node(gate);
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gate->rise_time(rise);
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gate->fall_time(fall);
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gate->decay_time(decay);
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break;
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case 2:
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gate = new NetLogic(scope, des->local_symbol(path),
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2, NetLogic::BUF);
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connect(gate->pin(0), sig->pin(0));
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connect(gate->pin(1), sub_sig->pin(0));
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des->add_node(gate);
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gate->rise_time(rise);
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gate->fall_time(fall);
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gate->decay_time(decay);
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gate = new NetLogic(scope, des->local_symbol(path),
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3, NetLogic::XOR);
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connect(gate->pin(0), sig->pin(1));
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connect(gate->pin(1), sub_sig->pin(0));
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connect(gate->pin(2), sub_sig->pin(1));
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des->add_node(gate);
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gate->rise_time(rise);
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gate->fall_time(fall);
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gate->decay_time(decay);
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break;
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default:
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cerr << get_line() << ": internal error: Wide unary "
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<< "minus not supported here." << endl;
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des->errors += 1;
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sig = 0;
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break;
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}
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break;
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default:
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cerr << "internal error: Unhandled UNARY '" << op_ << "'" << endl;
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sig = 0;
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}
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if (NetTmp*tmp = dynamic_cast<NetTmp*>(sub_sig))
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delete tmp;
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return sig;
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}
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/*
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* $Log: elab_net.cc,v $
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* Revision 1.60 2001/01/24 02:52:30 steve
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* Handle some special cases of unary 2's complement,
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* and improve netlist expression width handling.
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*
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* Revision 1.59 2001/01/18 03:16:35 steve
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* NetMux needs a scope. (PR#115)
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*
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